Apparatus for providing a striped covering on a wire



Nov. 5, 1957 B. w. LERCH 2,811,746

APPARATUS FOR PRQVIDING A STRIPED COVERING ON A WIRE Filed Sept. 4, 1956 FIG.

f INVENTOR. B W. LE'RCH -QilUmr yw- ATTORNEY United States Patent2,811,746 Patented Nov. 5, 1957 lice APPARATUS FOR PROVIDING A STRIPEDCOVERING ON A WIRE Brooke W. Lercll, Stoneleigh, Md., assignor toWestern Electric Company, Incorporated, New York, N. Y., a corporationof New York Application September 4, 1956, Serial No. 607,742

6 Claims. (Cl. 18-13) This invention relates to apparatus for coveringand striping a conductor, and more particularly to watercooled bafflesused for the protection of striping equipment in the manufacture ofcolor striped insulated conductors.

In the manufacture of cables used in the communications field, the cableis frequently composed of a plurality of insulated conductors. Becauseof the large number of similar conductors contained within a singlecable, it is necessary to provide means for identifying singleconductors or groups of conductors contained therein. A means ofidentifying the conductors is the application of coloring matter to theinsulation subsequent to extrusion; however, coloring matter placed onthermoplastic insulation, such as polyethylene, after the insulation hascooled and hardened tends to flake off because of the poor bond therebyproduced between the coloring matter and the insulation. In order toweld the coloring material to the conductor insulation, it has beendetermined that a desirable location for apparatus placing a coloredstripe or stripes on the continuously moving conductor is just adjacentto the extrusion orifice where the insulation is still hot and plastic.Two more desirable results of positioning the coloring apparatus at thispoint are that the hot wire quickly volatilizes the striping compoundsolvent thus preventing smearing, etc., and also the insulated conductormanufacturing line is thereby made shorter and more compact.

Because of the hot, plastic, easily damaged nature of the insulationcovering as it leaves the extrusion orifice, the striping needle squirtson the ink rather than contacts the insulation surface. For the samereason no guide sheaves or other possible damage causing devices areallowed to contact the surface of the insulation immediately after itsemerging from the extrusion orifice. This situation permits anincreasing amplitude of vibration in the wire as it leaves the extrusionorifice, which makes it desirable that the striping needle be locatedvery near to the head of the extruder so as to allow a smooth,uninterrupted and uniform stripe to be placed on the moving conductor.It is necessary to use inks in the striping equipment which havevolatile solvents in them such as acetone or the like so that the inkwill be completely dry before the fast moving conductor reaches the nextoperation in the production line. Because of the volatile nature of theink solvent, it is necessary that the striping device and needle be keptcool to prevent clogging of the ink supply in the striping needle.

One possibly obvious solution to this problem might be covering thestriping equipment with a coating of fibre glass or the like, however,such a solution would make it difficult for the operator to adjust thedelicate hypodermic type needle of the striping device and also wouldfail to shield the operators hands from the heat of the extruder whilehe makes adjustments.

It is, therefore, an object of this invention to prevent heat radiatedfrom the extrusion head from reaching the striping equipment.

Another object of the invention is to shorten the production line byallowing the striping device to be close to the extrusion orifice.

A further object is to produce a more uniform stripe on the conductor byallowing the striper to be located close to the extrusion orifice.

A related object is to prevent clogging of the ink emerging from theneedle of the striper.

Yet another object is to make possible the welding of the coloringmatter to the surface of the insulation while the surface is still hotand plastic.

Yet still another object is to protect the hands of the operator makingan adjustment on the striping device.

Other objects and features of the invention will be more readilyunderstood from the following detailed description, when read inconjunction with the accompanying drawings, in which:

Fig. 1 is a side elevation of an insulated conductor production line;

Fig. 2 is an expanded fragmental side elevation of the extruder head,striping device and liquid-cooled baifie, with part of the baffle brokenaway for clarity, and

Fig. 3 is a cross section taken along line 33 of Fig. 2 with portionsthereby broken away for clarity.

Referring now in detail to the drawing, Fig. 1 shows an extrusion linefor the extrusion of insulation around a moving conductor. The conductor13 is drawn by a capstan 22 from a supply reel 21 to an extrusion unit,indicated generally at 19, through the extrusion head 11, Where acovering of polyethylene or the like is eX- truded around it, andthrough a cylindrical opening 24 (Figs. 2 and 3) in a liquid-cooledbaffle 14 mounted on the extrusion unit 19 between a striping device 23and the extrusion head 11.

As the conductor advances in the direction of the capstan 22, ahypodermic type needle 12 (Figs. 2 and 3) of the color applicator 23squirts a stream of coloring fluid on the side of the covered conductor15 to produce a stripe thereon. The conductor is then drawn through awater trough 20, the principle purpose of which is to solidify theplastic insulation, but which also coagulates excessink and condensesfumes produced by the extruder 19. After passing around the capstan 22,the covered conductor 15 is drawn onto a powered takeup 26.

Referring to Figs. 2 and 3, the liquid-cooled baflle 14 must have aliquid tank 28 of sufficient height and width to protect the stripingequipment 23 from the heat of the extrusion head 11. As is shown in thefigures the tank is so located as to shield the striping device 23 fromthe head of the extruder and since the striping device is located abovethe advancing wire the major portion of the tank 28 is also locatedabove the wire. The small diameter and rapid movement of the coveredconductor emerging from the extruder head 11 make it necessary to locatethe striping needle 12 close to the extrusion orifice 27 of theextrusion head 11 because of the excessive vibration of the conductor asit moves away from the extrusion head. Therefore, the tank 28 mustnecessarily have a depth less than the distance between the extrusionhead and the striping equipment.

In order to produce the desired cooling with a slight depth, theliquid-cooled baflle must have an eflicient system of cooling which isprovided for by a cooling liquid inlet pipe 16 secured to and openinginto the upper portion of the tank 28, an overflow piping systemcomprising a hot liquid exhaust pipe 18 secured to the lower portion ofthe tank 28 and opening into the lower end of a drain pipe 17 projectingupwardly from the lower surface of the tank 28 and extending to a pointbelow and near, yet not in line with the'lower end of the pipe 16, sothat a cooling liquid flowing into the tank 28 from the inlet pipe 16will circulate through the tank 28 before entering the exhaust pipe 18.

. Operation As above described, the conductor 13 is drawn by the capstan22 through the extrusion head 11, where it is covered by polyethylene orlike insulation, through the liquid-cooled bafiie 14; under the stripingdevice 23; and through the water trough 20. As a result of the extruderoperation, heat radiates from the extrusion head 11 in all directions.Mounted on the extrusion unit 19 is the liquid-cooled baflie 14 betweenthe striping device 23 and the extrusion head 11. A cooling liquid, forexample water, is allowed to flow into the upper portion of the tank 28by the pipe 16, and fills the tank to the top of the drain pipe 17, intowhich the overflow exits and passes to the pipe 18. This arrangementmaintains a mass of relatively cold liquid in the tank 28 having a levelequal to the top of the drain pipe 17 because the cold liquid introducedby the pipe 16 goes to the bottom of the tank, and the heated liquidrises and overflows so that there is always a suflicient amount of coldliquid in the tank 28 to keep the heat of the extruder from reaching thestriping device 23 and evaporating the solvent in the striping compoundemerging from the needle 12, thus preventing clogging of the needle.

It is to be understood that the above-described arrangements are simplyillustrative of the application of the principles of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and wallwithin the spirit and scope theerof.

What is claimed is:

1. Apparatus for applying plastic insulation and color striping a movingconductor comprising an applicator for applying a coating of insulatingmaterial on a moving conductor, striping means of the type using astriping compound which is adversely atfected by heat, said stripingmeans being mounted adjacent to said applicator, and a liquid-cooledbaflie mounted between said applicator and said striping means forprotecting the striping means from the heat of the applicator.

2. Apparatus for applying plastic insulation and color striping a movingconductor comprising an applicator for applying a sheath of insulatingmaterial on a moving 4 conductor, a striping device of the type using astriping compound containing a volatile solvent, said striping devicebeing mounted adjacent to said applicator so that the moving conductorhas a minimum amount of vibration, and a liquid-cooled baflle mountedbetween said applicator and said striping device for protecting thestriping device from the heat of the applicator.

3. Apparatus for applying plastic insulation and color striping a movingconductor comprising an extruder having an extrusion orifice, coolingmeans for hardening the plastic insulation on the conductor after theinsulation has been extruded around the conductor, a striping device ofthe type using a striping compound containing a volatile solvent, saidstriping device being mounted between said extruder and said coolingmeans and adjacent to the extrusion orifice so that the moving conductorhas a minimum amount of vibration, and a liquidcooled baflle mountedbetween said extrusion orifice and said striping device for protectingthe striping device from the heat of the extruder.

4. Apparatus of claim 2 in which the liquid-cooled baflie comprises atank, a drain pipe having an inlet orifice which is located in the upperportion of said tank, and an inlet pipe opening into said tank andlocated so that a cooling liquid flowing into said tank from said inletpipe will circulate through the tank before entering said inlet orifice.

5. Apparatus of claim 3 in which the liquid-cooled bafllc comprises atank, a drain pipe having an inlet orifice which is located in the upperportion of said tank, and an inlet pipe opening into said tank andlocated so that a cooling liquid flowing into said tank from said inletpipe will circulate through said tank before entering said inletorifice.

6. Apparatus of claim 3 in which said liquid-cooled batfle comprises atank, an overflow pipe projecting through and upwardly from the lowersurface of the tank and extending upwardly to a point below and near theupper surface of said tank, and an inlet pipe secured to and openinginto the upper portion of said tank and located so that a cooling liquidflowing into said tank from said inlet pipe will circulate through saidtank before entering said overflow pipe.

Gray Oct. 9, 1956 Russell Apr. 14, 1953

